Tanya is Derek Delgado's sister-in-law. She and his brother, Jake, had their son, Miles, when they were still in high school. At first, she and Debbie become good friends however their relationship gets strained when Debbie Gallagher tricks Derek into fathering Franny Gallagher. Later, when Tanya and Mrs. Delgado try to take Franny away from Debbie when they deem her unfit as a mother. Then Tanya and Mrs. Delgado were threatened, when Debbie's mother Monica Gallagher returns with a bat to help Debbie reclaimed her daughter.
Season 5[]
Tanya is first introduced in episode 10 of season 5 ("South Side Rules"). Debbie joins Derek for a family picnic where she meets Tanya who she initially thinks is Derek's sister but as it turns out she's his sister-in-law and she's related to Derek through the child she had with his older brother, Jake. She reveals in her conversation with Debbie as she paints her nails that she doesn't get along with her real family as her father's in prison and her mother's an alcoholic, but once she met Jake and had Miles the Delgados accepted her like one of their own.
Season 6[]
Tanya appears in episode 2 of season 5 ("#AbortionRules") and her attitude towards Debbie has obviously changed. Debbie appears at the nail shop where Tanya works asking of Derek's whereabouts and why she can't seem to reach him. Debbie is confused about why Derek and his family have been so distant towards her because when Tanya got pregnant with Jake's baby they accepted her with open arms. Tanya then begrudgingly tells Debbie that it wasn't Derek's parents that made him move to Florida but he wanted to do it himself because he wasn't ready to be a father. She explains that Debbie scared him among other things about Derek that she didn't know because Debbie never truly took the time out to get to know him. She then ends it with saying that "Guys like to feel supported. Not trapped." When Debbie tells Tanya that she didn't mean to "trap" Derek, Tanya shows some understanding but in the end holds true to what she said before.
Season 7[]
Tanya plays a more significant role in season 7. She first appears in episode 5 ("Own Your Shit!", when she bumps into Debbie, who is pretending to be homeless and panhandling with Franny on a street corner to pay her dues with Fiona. Tanya is shocked to see Debbie supposedly homeless and she shows concern for the mother and daughter in their conversation. Shortly after talking— while Tanya is only a few dozen feet away— Debbie and a homeless woman engage in a verbal fight that escalates physically. Tanya anxiously watches this confrontation, while onlookers record. In the episodes that follow, we see that Tanya took the footage to DCFS (Department of Child and Family Services), forcing Debbie to prove that she's a capable mother and hasn’t endangered or neglected Franny.
In episode 8 ("You Sold You the Laundromat, Remember?") Debbie shows Ms. Delgado and Tanya around her and Neil's home to show that she has a good place for Franny to stay and that she isn't indeed homeless. Tanya and Ms. Delgado are happy to meet the baby but they obviously aren't to keen on Debbie herself. Later on the episode it is revealed that after they left Debbie and Neil's house they came back when Debbie was gone and kidnapped Franny.
Debbie's mother Monica Gallagher returns and they visit the house. Monica then reclaims her granddaughter after terrorizing the house and scaring the Delgado Family.
The last episode Tanya is seen in season 7 is episode 9 ("Ouroboros") where she and her mother-in-law Ms. Delgado are with Debbie and her mother at the DCFS meeting in order to gain custody of Franny. In the end, the official tells Tanya and Ms. Delgado not to try to steal the baby again since Debbie is the mother and the latter is allowed to keep custody over Franny, provided she and her family don't terrorize the Delgado's again. Tanya and Ms. Delgado are granted visitation rights, which they begrudgingly accept.